An epitaxial layer is growing when we are using low working pressure, low rf (radio frequency) power and high substrate temperature. Why is this epitaxial layer growing? What are the reasons for this epitaxial layer growth and how does one prevent this epitaxial growth ?
Hi, the crystal is thermodynamically more stable than the amorphous phase. If you use lower temperature or higher pressure, kinetics will limit deposition and you will end up with a disordered film. Most people prefer the crystalline form, in particular if it is single crystalline!
Thomas Walther sir can you explain in detail how an epitaxial layer is forming ? but many reports saying that in a-Si:H/c-Si heterojunction solar cells, formation of the epitaxial Si deteriorate the surface passivation properties because of the increased number of defect states in the interfacial layer resutling in decrease in efficiency of the cell and the a-Si:H layers formed at low substrate temperature typically contains many defects and are not favorable for surface passivation .
Venkat, do you mean that a-Si has fewer point defects than an a-Si/c-Si interface? That may depend on the roughness of the interface; the most point defects you will probably get for polycrystalline Si with tiny grains.
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